research project. 2. To administer a standardized behavioral test battery to all subjects. 3. To collaborate with Project PIs to relate the diagnostic findings to experimental findings obtained in Project studies. Selection of the standardized test battery was governed by several factors that resulted in the following: 1. Measures that will allow us to test children across a range of ages. 2. Measures that examine a variety of intellectual and cognitive abilities. 3. Measures that can be administered and scored relatively quickly so that subject inclusion decisions can be made in a timely fashion. 4. Measures that are better suited to or can be adapted for children with specific impairments. The resulting battery consists of standardized tests, questionnaires and evaluations that allow us to assess critical aspects of speech, hearing, language, attention, visual-spatial ability, and general cognition.